Detection of coagulase gene in Staphylococcus aureus from several dairy farms in East Java, Indonesia, by polymerase chain reaction

Aim:

This study was conducted to study the coagulase (coa) gene-based genetic diversity of Staphylococcus aureus, isolated from different samples of cattle from three different regions in East Java Province, Indonesia.

Materials and Methods:

A total of 160 raw milk samples collected in East Java Province, Indonesia, were screened for the presence of S. aureus. The presumptive isolates were confirmed by coa test. The confirmed S. aureus isolates were subjected to coa gene polymerase chain reaction.

Results:

Of 160 different samples, 20 (12.5%) isolates of S. aureus were confirmed by positive coa test. Of 20 S. aureus isolates, 19 (95%) isolates carried coa gene. Six different genotypes of coa gene, i.e., 440 bp, 510 bp, 547 bp, 680 bp, 740 bp, and 820 bp were obtained. One coa genotypes, 510 bp (10 isolates) were observed in polymorphism to be more prevalent than the others, and the genotype was present in at least one isolates from every region.

Conclusion:

It can be concluded that coa gene is easily epidemiological tool for detection of variation strain from S. aureus.

First reported case of Staphylococcus condimenti infection associated with catheter-related bacteraemia

We report a case of a patient who experienced a catheter-related bloodstream infection caused by Staphylococcus condimenti, which was first isolated from soy sauce mash. This is the first reported case of human infection. Although blood culture isolates and the catheter tip tube did not reveal coagulase or clumping factor, false-positive results were obtained from latex agglutination tests for clumping factor and protein A due to self-agglutination. Care is needed when performing only latex agglutination test without a coagulase test. Further studies are needed to determine the pathogenic potential of S. condimenti based on appropriate identification.

Identification and Differentiation of Coagulase-Negative Staphylococcus aureus by Polymerase Chain Reaction

Staphylococcus aureus is an etiological agent of a wide variety of human and animal infections. The majority of S. aureus are coagulase-positive; however, some may be atypical in that they do not produce coagulase. Incorrect identification of an isolate can impact implementation of effective treatment and/or control measures. In this study, polymerase chain reaction-based DNA fingerprinting was used to differentiate coagulase-positive Staphylococcus aureus (CPSA) from coagulase-negative Staphylococcus aureus (CNSA). A total of 29 CNSA and 50 CPSA were evaluated. PCR-based DNA fingerprinting differentiated CNSA from CPSA on the basis of visible observation and densitometric evaluation. The method is rapid and accurate, eliminating variability associated with conventional techniques.

Modification of the Conventional Procedure for the Test of Staphylococcal Coagulase

The coagulase test is routinely used for the confirmation of suspect Staphylococcus aureus on Baird-Parker agar (BPA). Overnight (18 to 24 h) preincubation of suspect colonies in brain heart infusion (BHI) broth is generally practiced prior to the coagulase test. In order to shorten the test protocol, different preincubation times of S. aureus in BHI were evaluated. Stock cultures (257 strains) of S. aureus were subcultured on BPA, and single colonies of each strain on BPA were analyzed for coagulase activities by the conventional procedure except that the preincubation times in BHI were varied (0, 4, and 24 h). The formation of a clot was examined at 2-h intervals over a 6-h period and at 24 h, and any degree of clot formation (1+ to 4+) was considered a positive reaction. Low sensitivities were found for tests without preincubation in BHI prior to the enzyme test. However, for 4- and 24-h preincubation, there was no difference in the degree of clot formation and in the sensitivities of the coagulase tests with incubation periods from 6 (98.1%) to 24 h (99.6%). Compared with the conventional procedures which may need two days, the modified protocol (4-h preincubation in BHI) can identify a large majority (97.7-98.1 %) of suspect S. aureus on BPA within one working day.